// Package govultr contains the functionality to interact with the Vultr public
// HTTP REST API.
package govultr

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net"
	"net/http"
	"net/url"
	"strings"
	"time"

	"github.com/hashicorp/go-retryablehttp"
)

const (
	version     = "3.24.0"
	defaultBase = "https://api.vultr.com"
	userAgent   = "govultr/" + version
	rateLimit   = 500 * time.Millisecond
	retryLimit  = 3
)

// RequestBody is used to create JSON bodies for one off calls
type RequestBody map[string]interface{}

// Client manages interaction with the Vultr API
type Client struct {
	// Http Client used to interact with the Vultr API
	client *retryablehttp.Client

	// BASE URL for APIs
	BaseURL *url.URL

	// User Agent for the client
	UserAgent string

	// Services used to interact with the API
	Account                  AccountService
	Application              ApplicationService
	Backup                   BackupService
	BareMetalServer          BareMetalServerService
	Billing                  BillingService
	BlockStorage             BlockStorageService
	CDN                      CDNService
	ContainerRegistry        ContainerRegistryService
	Database                 DatabaseService
	Domain                   DomainService
	DomainRecord             DomainRecordService
	FirewallGroup            FirewallGroupService
	FirewallRule             FireWallRuleService
	Instance                 InstanceService
	ISO                      ISOService
	Kubernetes               KubernetesService
	LoadBalancer             LoadBalancerService
	Logs                     LogsService
	Marketplace              MarketplaceService
	ObjectStorage            ObjectStorageService
	OS                       OSService
	Plan                     PlanService
	Region                   RegionService
	ReservedIP               ReservedIPService
	Inference                InferenceService
	Snapshot                 SnapshotService
	SSHKey                   SSHKeyService
	StartupScript            StartupScriptService
	SubAccount               SubAccountService
	User                     UserService
	VirtualFileSystemStorage VirtualFileSystemStorageService
	VPC                      VPCService
	// Deprecated: VPC2 is no longer supported
	VPC2 VPC2Service

	// Optional function called after every successful request made to the Vultr API
	onRequestCompleted RequestCompletionCallback
}

// RequestCompletionCallback defines the type of the request callback function
type RequestCompletionCallback func(*http.Request, *http.Response)

// NewClient returns a Vultr API Client
func NewClient(httpClient *http.Client) *Client {
	if httpClient == nil {
		httpClient = &http.Client{
			Transport: &http.Transport{
				DialContext: (&net.Dialer{
					Timeout:   90 * time.Second,
					KeepAlive: 90 * time.Second,
					DualStack: true,
				}).DialContext,
				MaxIdleConns:          100,
				IdleConnTimeout:       90 * time.Second,
				TLSHandshakeTimeout:   30 * time.Second,
				ExpectContinueTimeout: 1 * time.Second,
				MaxIdleConnsPerHost:   -1,
				DisableKeepAlives:     true,
			},
			Timeout: 60 * time.Second,
		}
	}

	baseURL, _ := url.Parse(defaultBase)

	client := &Client{
		client:    retryablehttp.NewClient(),
		BaseURL:   baseURL,
		UserAgent: userAgent,
	}

	client.client.HTTPClient = httpClient
	client.client.Logger = nil
	client.client.ErrorHandler = client.vultrErrorHandler
	client.SetRetryLimit(retryLimit)
	client.SetRateLimit(rateLimit)

	client.Account = &AccountServiceHandler{client}
	client.Application = &ApplicationServiceHandler{client}
	client.Backup = &BackupServiceHandler{client}
	client.BareMetalServer = &BareMetalServerServiceHandler{client}
	client.Billing = &BillingServiceHandler{client}
	client.BlockStorage = &BlockStorageServiceHandler{client}
	client.ContainerRegistry = &ContainerRegistryServiceHandler{client}
	client.CDN = &CDNServiceHandler{client}
	client.Database = &DatabaseServiceHandler{client}
	client.Domain = &DomainServiceHandler{client}
	client.DomainRecord = &DomainRecordsServiceHandler{client}
	client.FirewallGroup = &FireWallGroupServiceHandler{client}
	client.FirewallRule = &FireWallRuleServiceHandler{client}
	client.Instance = &InstanceServiceHandler{client}
	client.ISO = &ISOServiceHandler{client}
	client.Kubernetes = &KubernetesHandler{client}
	client.LoadBalancer = &LoadBalancerHandler{client}
	client.Logs = &LogsServiceHandler{client}
	client.Marketplace = &MarketplaceServiceHandler{client}
	client.ObjectStorage = &ObjectStorageServiceHandler{client}
	client.OS = &OSServiceHandler{client}
	client.Plan = &PlanServiceHandler{client}
	client.Region = &RegionServiceHandler{client}
	client.ReservedIP = &ReservedIPServiceHandler{client}
	client.Inference = &InferenceServiceHandler{client}
	client.Snapshot = &SnapshotServiceHandler{client}
	client.SSHKey = &SSHKeyServiceHandler{client}
	client.StartupScript = &StartupScriptServiceHandler{client}
	client.SubAccount = &SubAccountServiceHandler{client}
	client.User = &UserServiceHandler{client}
	client.VirtualFileSystemStorage = &VirtualFileSystemStorageServiceHandler{client}
	client.VPC = &VPCServiceHandler{client}
	client.VPC2 = &VPC2ServiceHandler{client}

	return client
}

// NewRequest creates an API Request
func (c *Client) NewRequest(ctx context.Context, method, uri string, body interface{}) (*http.Request, error) {
	resolvedURL, err := c.BaseURL.Parse(uri)
	if err != nil {
		return nil, err
	}

	buf := new(bytes.Buffer)
	if body != nil {
		if err2 := json.NewEncoder(buf).Encode(body); err2 != nil {
			return nil, err2
		}
	}

	req, err := http.NewRequestWithContext(ctx, method, resolvedURL.String(), buf)
	if err != nil {
		return nil, err
	}

	req.Header.Add("User-Agent", c.UserAgent)
	req.Header.Add("Accept", "application/json")
	req.Header.Add("Content-Type", "application/json")

	return req, nil
}

// DoWithContext sends an API Request and returns back the response. The API response is checked  to see if it was
// a successful call. A successful call is then checked to see if we need to unmarshal since some resources
// have their own implements of unmarshal.
func (c *Client) DoWithContext(ctx context.Context, r *http.Request, data interface{}) (*http.Response, error) {
	rreq, err := retryablehttp.FromRequest(r)
	if err != nil {
		return nil, err
	}

	rreq = rreq.WithContext(ctx)

	res, errDo := c.client.Do(rreq)

	if c.onRequestCompleted != nil {
		c.onRequestCompleted(r, res)
	}

	if errDo != nil {
		return nil, errDo
	}

	defer func() {
		if rerr := res.Body.Close(); err == nil {
			err = rerr
		}
	}()

	body, err := io.ReadAll(res.Body)
	if err != nil {
		return nil, err
	}

	res.Body = io.NopCloser(bytes.NewBuffer(body))

	if res.StatusCode >= http.StatusOK && res.StatusCode <= http.StatusNoContent {
		if data != nil {
			if err := json.Unmarshal(body, data); err != nil {
				return nil, err
			}
		}
		return res, nil
	}

	return res, errors.New(string(body))
}

// SetBaseURL Overrides the default BaseUrl
func (c *Client) SetBaseURL(baseURL string) error {
	updatedURL, err := url.Parse(baseURL)

	if err != nil {
		return err
	}

	c.BaseURL = updatedURL
	return nil
}

// SetRateLimit Overrides the default rateLimit. For performance, exponential
// backoff is used with the minimum wait being 2/3rds the time provided.
func (c *Client) SetRateLimit(t time.Duration) {
	c.client.RetryWaitMin = t / 3 * 2
	c.client.RetryWaitMax = t
}

// SetUserAgent Overrides the default UserAgent
func (c *Client) SetUserAgent(ua string) {
	c.UserAgent = ua
}

// OnRequestCompleted sets the API request completion callback
func (c *Client) OnRequestCompleted(rc RequestCompletionCallback) {
	c.onRequestCompleted = rc
}

// SetRetryLimit overrides the default RetryLimit
func (c *Client) SetRetryLimit(n int) {
	c.client.RetryMax = n
}

func (c *Client) vultrErrorHandler(resp *http.Response, err error, numTries int) (*http.Response, error) {
	if resp == nil {
		if err != nil {
			return nil, fmt.Errorf("gave up after %d attempts, last error : %s", numTries, err.Error())
		}
		return nil, fmt.Errorf("gave up after %d attempts, last error unavailable (resp == nil)", numTries)
	}

	buf, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("gave up after %d attempts, last error unavailable (error reading response body: %v)", numTries, err)
	}
	return nil, fmt.Errorf("gave up after %d attempts, last error: %#v", numTries, strings.TrimSpace(string(buf)))
}

// BoolToBoolPtr helper function that returns a pointer from your bool value
func BoolToBoolPtr(value bool) *bool {
	return &value
}

// StringToStringPtr helper function that returns a pointer from your string value
func StringToStringPtr(value string) *string {
	return &value
}

// IntToIntPtr helper function that returns a pointer from your string value
func IntToIntPtr(value int) *int {
	return &value
}
